MATH: Permutations and combinations HELP!!?

If you do not know the formula, a good way to tackle this sort of problem is to start with what if the test contains just 1 question? How many combinations are there?

Well the answer to this question is of couse 4 answer sheets are possible, each answer could occur.

Now let us try 2 questions. Call the answers to each question A, B, C, D. I denote them as 1A, 1B , ... 2A, 2B, .... for simplicity. 1A, 2A is possible, 1A, 2B is possible, .... 1D,2D is possible. How many is that? That is 16 answer sheets possible.

For 3 questions it is 64 answer sheets are possible I will tell you without having to go through the whole process, but you are free to do so if it pleases you.

Do you see a pattern? May require a calculator, but you should be able to get the answer now. Just follow the pattern which has appeared. From here, perhaps you can get a good understanding of what the formula in general would be for any # of questions and any # of possible responses.